Do not cite bad papers (if possible)

Post inspired by this tweet: @worrydream: Citing bad papers encourages bad papers. Don’t struggle through a bad paper, ignore it

Of course, I agree with the “spirit” of the idea but as usual, its practical implementation is more difficult than it seems:

PC members (i.e. potential reviewers for your paper) may get very angry if your paper is related to their previous work and you don’t cite it (whether it´s a good or bad paper). I should add that apart from citing it, you should do it in a very polite way, explaining why yours is better but without criticizing too much
PC members may know popular bad papers without being aware they are bad. If you don’t cite them, they may think you are missing important related work (it´s completely unrealistic to assume they will check themselves whether you´re not citing one specific paper because it´s just crap). You should cite all well-known papers in the area regardless their quality.

Of course these two reasons favor the citing of bad papers which only aggravates the situation but nobody said life was easy!

Let me just add that bad papers are another reason why evaluating the work of a researcher based on the number of citations he/she gets is a very bad idea.